I hear a lot of talk about how good motorcraft 5w20 is and that it's basically a syn blend oil. Does the same hold true for the 5w30 weight? currently I'm using either Penzoil, Halvoline, in one vehicle and M1 5w30 in another. It'd be nice to keep one oil stocked for both. (02 Protoge) and (03 Silverado) thanks.